Back-up Power and Hands-on Training
Submitted by umaruba on Thu, 2009-02-26 13:40.
Hands-on training are the current trend in training recently but the issue of power remains vital on its success. therefore the need to have a standard tran-sient power supply at a training site. this of course in the developing countries. my proposed topic is to intimate our policy makers on the need to to understudy the various systems that operate 24/7 operations and built into our educational systems. this will not only even make a power-fail-free training session but that we will be able to build and apply in our various operations.
Re: Back-up Power and Hands-on Training
How do I select the proper UPS for a security application?
PHOTO COURTESY OF TRIPP LITE
An uninterruptible power supply (UPS) provides backup AC power for connected devices, allowing an orderly shutdown of computer equipment in the event of a power failure or blackout. As electronic security systems become integrated with network equipment, providing for backup power has become another important issue that systems integrators must address during the planning and installation phases of a project.
There are three basic issues when considering the installation of a UPS. The first is how much current is needed, and for how long. A UPS typically provides 110VAC power through a common type of grounded outlet, to which a power strip with the devices to be backed up are connected. Manufacturers will generally provide an Internet Web page calculator that will help determine which of their units would be the proper selection for a specific installation. One such UPS calculator is available at Tripplite’s Web page, http://www.tripplite.com/selector/ ups_index.cfm.
Once the number of computers or other devices are added up, along with the amount of standby time required, the calculator will provide a recommendation.
While it is a straightforward proposition to determine the power requirements, it is important for security installation companies to understand that there are actually three distinct UPS types, each providing different levels of surge and brownout protection for the devices connected to it.
The economy model of UPS is generally termed a standby backup offline (SBO) device. This product provides direct connection between utility power and the protected computer equipment, with the same level of surge protection found in an inexpensive plug-in surge protector six-pack extension cord. If power fails, the UPS will switch on the battery backup, which is connected through an inverter that converts the DC power from the battery into 60-hertz AC. This emergency power is generally available for only a few minutes, which is enough time to shut down running programs and computers in an orderly manner. (Of course, this assumes that a quick-thinking and acting person is on hand at the time of the power failure.)
The next increment in UPS protection is the line interactive (LI) UPS. These devices have all of the characteristics of an SBO, with the addition of a power-line monitoring function, which can add power from the battery pack to make up for brownout voltage deficiencies. This voltage regulation feature is important, and worth the increased cost.
The top level of protection is provided by the on-line type of UPS, which provides a complete electrical firewall between any connected devices and utility power service. Incoming AC power is conditioned and provided in a three-step process.
First, the AC current is converted into DC and filtered through capacitors, which remove transients, harmonic distortion, and other unwanted elements. The backup batteries are connected at this first stage, so that when their power is drawn, it is filtered and conditioned by the on-line UPS before reaching the connected local devices.